[Cerebrospinal fluid beta-endorphin in congenital insensitivity to pain].

Spontaneously elevated nociceptive threshold levels were markedly diminished after Naloxone injections in 4 patients with congenital insensitivity to pain. This finding suggested the hypothesis of a relation between congenital insensitivity to pain and permanent hyperfunction of an endomorphinic system. Radio-immunoassay of CSF beta-endorphin was performed in all 4 cases. The normal or only slightly elevated levels cannot explain electrophysiologic findings, but as a function of the multiplicity of endogenous opioid systems, hyperactivity of another endomorphinic system cannot be excluded. Other hypotheses may also be proposed.